[Doc] add build-in style document (#633)

docs/markdown/en-US/built-in-style.md

@@ -0,0 +1,48 @@
+## Built-in Style
+Vant contains some common styles that can be used directly by the className.
+
+### Text ellipsis
+When the text content length exceeds the maximum container width, the excess text is automatically omitted.
+
+```html
+<div class="van-ellipsis">
+  This is a paragraph of 250px width limit, the back will be omitted.
+</div>
+```
+
+### Hairline
+Add 1px border under the Retina screen for the element, based on a pseudo element.
+
+```html
+<!-- border top -->
+<div class="van-hairline--top"></div>
+
+<!-- border bottom -->
+<div class="van-hairline--bottom"></div>
+
+<!-- border left -->
+<div class="van-hairline--left"></div>
+
+<!-- border right -->
+<div class="van-hairline--right"></div>
+
+<!-- border top & bottom -->
+<div class="van-hairline--top-bottom"></div>
+
+<!-- full border -->
+<div class="van-hairline--surround"></div>
+```
+
+### Animation
+
+```html
+<!-- fade in  -->
+<transition name="van-fade">
+  <div v-show="visible">Fade</div>
+</transition>
+
+<!-- slide bottom -->
+<transition name="van-slide-bottom">
+  <div v-show="visible">Fade</div>
+</transition>
+```

docs/markdown/en-US/coupon.md

@@ -107,8 +107,8 @@ export default {
 | discount | Discount | `Number` |
 | denominations | Denominations | `Number` |
 | origin_condition | Condition | `Number` |
-| start_at | Start time | `Number` |
-| end_at | End time | `Number` |
+| start_at | Start time (Timestmap, unit second) | `Number` |
+| end_at | End time (Timestmap, unit second) | `Number` |
 | reason | Unavailable reason | `String` |
 | value | Value | `Number` |
 

docs/markdown/index.js

@@ -18,6 +18,7 @@ export default {
   'zh-CN/address-list': wrapper(r => require.ensure([], () => r(require('./zh-CN/address-list.md')), 'zh-CN/address-list')),
   'zh-CN/area': wrapper(r => require.ensure([], () => r(require('./zh-CN/area.md')), 'zh-CN/area')),
   'zh-CN/badge': wrapper(r => require.ensure([], () => r(require('./zh-CN/badge.md')), 'zh-CN/badge')),
+  'zh-CN/built-in-style': wrapper(r => require.ensure([], () => r(require('./zh-CN/built-in-style.md')), 'zh-CN/built-in-style')),
   'zh-CN/button': wrapper(r => require.ensure([], () => r(require('./zh-CN/button.md')), 'zh-CN/button')),
   'zh-CN/card': wrapper(r => require.ensure([], () => r(require('./zh-CN/card.md')), 'zh-CN/card')),
   'zh-CN/cell-swipe': wrapper(r => require.ensure([], () => r(require('./zh-CN/cell-swipe.md')), 'zh-CN/cell-swipe')),
@@ -72,6 +73,7 @@ export default {
   'en-US/address-list': wrapper(r => require.ensure([], () => r(require('./en-US/address-list.md')), 'en-US/address-list')),
   'en-US/area': wrapper(r => require.ensure([], () => r(require('./en-US/area.md')), 'en-US/area')),
   'en-US/badge': wrapper(r => require.ensure([], () => r(require('./en-US/badge.md')), 'en-US/badge')),
+  'en-US/built-in-style': wrapper(r => require.ensure([], () => r(require('./en-US/built-in-style.md')), 'en-US/built-in-style')),
   'en-US/button': wrapper(r => require.ensure([], () => r(require('./en-US/button.md')), 'en-US/button')),
   'en-US/card': wrapper(r => require.ensure([], () => r(require('./en-US/card.md')), 'en-US/card')),
   'en-US/cell-swipe': wrapper(r => require.ensure([], () => r(require('./en-US/cell-swipe.md')), 'en-US/cell-swipe')),

docs/markdown/zh-CN/built-in-style.md

@@ -0,0 +1,47 @@
+## 内置样式
+Vant 中默认包含了一些常用样式，可以直接通过 className 的方式使用。
+
+### 文字省略
+当文本内容长度超过容器最大宽度时，自动省略多余的文本。
+
+```html
+<div class="van-ellipsis">这是一段宽度限制 250px 的文字，后面的内容会省略</div>
+```
+
+### 1px 边框
+为元素添加 Retina 屏幕下的 1px 边框（即 hairline），基于伪类 transform 实现。
+
+```html
+<!-- 上边框 -->
+<div class="van-hairline--top"></div>
+
+<!-- 下边框 -->
+<div class="van-hairline--bottom"></div>
+
+<!-- 左边框 -->
+<div class="van-hairline--left"></div>
+
+<!-- 右边框 -->
+<div class="van-hairline--right"></div>
+
+<!-- 上下边框 -->
+<div class="van-hairline--top-bottom"></div>
+
+<!-- 全边框 -->
+<div class="van-hairline--surround"></div>
+```
+
+### 动画
+可以通过 `transition` 组件使用内置的动画
+
+```html
+<!-- 淡入 -->
+<transition name="van-fade">
+  <div v-show="visible">Fade</div>
+</transition>
+
+<!-- 下滑 -->
+<transition name="van-slide-bottom">
+  <div v-show="visible">Fade</div>
+</transition>
+```

docs/markdown/zh-CN/coupon.md

@@ -110,8 +110,7 @@ export default {
 | discount | 折扣（0为满减券）88=>8.8折 | `Number` |
 | denominations | 面值（0为折扣券）单位分 | `Number` |
 | origin_condition | 满减条件（0为无门槛，满XX元可用）单位分 | `Number` |
-| start_at | 卡有效开始时间 | `Number` |
-| end_at | 卡失效日期 | `Number` |
+| start_at | 卡有效开始时间 (时间戳, 单位秒) | `Number` |
+| end_at | 卡失效日期 (时间戳, 单位秒) | `Number` |
 | reason | 不可用原因 | `String` |
 | value | 订单优惠金额，单位分 | `Number` |
-